Water-Soluble Unit Dose Film Composition for Cold-Wash Dissolution
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Solution Overview
Problem
Water-soluble unit dose articles made with traditional polyvinyl alcohol films face issues of incomplete dissolution during short and cold wash cycles, leading to undissolved film material deposition, and seal failures between the films result in premature rupture.
Innovation Solution
A water-soluble unit dose article comprising a first and second water-soluble film, where the first film contains a blend of polyvinyl alcohol polymers with carboxylated anionic monomer units and a higher proportion of homopolymer, and the second film consists mainly of polyvinyl alcohol homopolymer with a specific viscosity, sealed using a solvent sealing solution predominantly composed of water, to enhance film integrity and reduce seal failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional polyvinyl alcohol films are used in water-soluble unit dose articles, then the films provide sufficient structural integrity during storage and transport, but the films suffer from incomplete dissolution during short and cold wash cycles resulting in undissolved film material deposition
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyvinyl alcohol film by incorporating carboxylated anionic monomer units (3-6 mol.%) and adjusting the blend ratio between copolymer and homopolymer. These parameter changes enable the film to maintain structural integrity while achieving complete dissolution under short and cold wash conditions, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent creates a composite polyvinyl alcohol material by blending two different PVOH polymers with distinct properties: one providing structural strength and the other enhancing dissolution. This composite approach allows the film to exhibit both sufficient structural integrity and complete dissolution behavior, simultaneously addressing both requirements.
2Productivity
If polyvinyl alcohol films with higher homopolymer content are used to improve dissolution, then dissolution performance improves, but seal failures occur resulting in premature rupture
Solution Approach 1:
The patent optimizes the compositional parameters by limiting homopolymer content to 35-90% (rather than using high homopolymer content) and adjusting the carboxylated monomer unit content to 3-6 mol.%. This balanced parameter selection ensures both complete dissolution and adequate seal integrity, preventing the premature rupture caused by excessive homopolymer content.
Solution Approach 2:
The patent applies different polymer compositions to different functional regions: the film body uses a balanced blend for dissolution, while the seal areas maintain sufficient polymer strength for sealing reliability. This local differentiation of material properties allows the film to achieve complete dissolution without compromising seal integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures complete dissolution of the film under short and cold wash cycles while maintaining structural integrity and reducing seal failures, ensuring the contents are released into the wash liquor effectively.
Implementation Method 1
sealed using a solvent sealing solution predominantly composed of water
Implementation Method 2
when the water-soluble unit dose article is added to water, the film dissolves/disintegrates releasing the internal contents into the surrounding water
Data Source
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AI summary
Water-soluble unit dose article and a method of making.